| Title | Subsurface Structural Mapping Using 2D MT and Gravity Data of Dieng Geothermal Field, Indonesia |
|---|---|
| Authors | M. Istiawan NURPRATAMA, Catra Adiwardhana DARUSMAN |
| Year | 2015 |
| Conference | World Geothermal Congress |
| Keywords | 2D MT, gravity, geophysics, geology, subsurface structural, mapping, geothermal, Dieng |
| Abstract | Dieng Field is located in Central Java, Indonesia with 63 km2 of Concession Area. Dieng field also known as Vulcan Complex Area. About 47 wells have been drilled to prove potential geothermal resources of this field and able to generate electricity for Unit 1 (1x60 MW). For Unit 2&3 Development purposes, resource assessment has been doing in Dieng Field, including reservoir modeling and evaluation of surface & subsurface structural mapping. In this study, we attempt to evaluate subsurface structural pattern on this area using integrated interpretation of existing 2D MT and gravity data. The gravity survey of Dieng area is about 16 Km2 x 14 Km2 using approximately 371 gravity stations with 500 m spacing inside Dieng Concession Area and 1000 m spacing beyond. The MT survey of Dieng area is about 10 Km2 x 8 Km2 using approximately 285 MT stations and 173 TDEM stations. About 200 gravity stations and 100 MT & TDEM stations have been used for further evaluation regarding prospective area boundaries. For Gravity Analysis, second vertical derivative analysis is conducted to trace deep fault controlling Dieng area which results striking NW-SE, E-W and SW-NE. For MT Analysis, resistivity discontinuities and TE-TM curve splitting analysis are conducted to trace possible fault pattern from 2D MT Section which result striking NW-SE, E-W, NE-SW and N-S. Integrated subsurface structural mapping from both 2D MT and Gravity data combined with detail surface structural mapping will give us an understanding of structural play controlled Dieng Field. |